The primary functions of this core facility are to manage the breast cancer cell line repository and to provide essential tissue culture support to breast cancer researchers. The facility provides shared tissue culture areas that are well equipped and stocked with all of the necessary tissue culture reagents and supplies. Breast cancer cell lines are cultured and made available to investigators as either growing or frozen cell stocks. Frozen cell stocks are replenished as required. DNA fingerprinting of cell lines is used as a quality control measure. The breast cancer cell line repository is managed through a complete inventory system. The individual cell lines of the repository are described in a computer database that is part of the SPORE computer network. A number of tissue culture related services are offered, including mycoplasma testing, helper virus rescue assays, charcoal stripping of calf serum, cell culture, cell freezing, and growth curve analysis of new lots of both calf serum and fetal calf serum. The production of primary cell lines from normal breast tissue and from breast cancer primary or metastatic tumors is a developing service. The shared tissue culture areas are used by the investigators, trainees and technicians from Il LCRC breast cancer research laboratories who do not have their own individual tissue culture space. The breast cancer cell line repository is used by 13 breast cancer research laboratories. All of the breast cancer research laboratories regularly request mycoplasma testing. The helper virus rescue assay has been used by four breast cancer research laboratories. Charcoal stripped calf serum produced in the core facility is used by seven breast cancer research laboratories. The cell culture service has been used by eight breast cancer research laboratories.